Impact-induced vibrations that travel along a human body part, such as a tendon or ligament, may lead to muscle or joint fatigue, or even injury. For example, a vibrating tennis racket held in the hand will transmit longitudinally and radially traveling vibrations into the hand, wrist, elbow, upper arm and shoulder. For some, these repeated vibrations lead to a painful injury termed “tennis elbow”.
Several methods for isolating or reducing vibrations are discussed in the prior art. For example, a dampening device containing one or more springs may be attached directly to racket strings to try to dampen string-induced vibrations before the vibrations reach the racket handle. While effective to some degree, such devices do not completely eliminate vibrations from being transmitted to the hand, wrist, forearm, elbow, etc.
An alternative vibration reducing method is to apply a vibration absorber to the vibration source (sometimes termed an “active” or “dynamic” vibration absorber). Dynamic vibration absorbers use a mass-spring combination that can be tuned to exert a force equal and opposite to a sensed vibration. Dynamic vibration absorbers require an electronic power source and are not considered practical for use in racket sports.
Yet another alternative is a “passive” vibration absorber, which incorporates mechanical means such as a mass-spring-fluid combination, to dampen excessive unwanted vibrations. To be effective, passive vibration absorbers require a means to apply a counter force to a vibration, such as with automobile shock absorbers that have a spring, a piston and fluid forced by the piston from one chamber into another chamber.
A number of supports and braces have been proposed for use to treat “tennis elbow” and other impact-induced shock on the human elbow joint. For example, U.S. Pat. No. 5,865,775 discloses a forearm sleeve 10 with an energy-attenuating viscoelastic means 50 affixed to such sleeve. A tension strap 32 is wrapped around the sleeve to counter forces directed radially outwardly from the sleeve and the viscoelastic means 50. Such sleeve and band combination purports to dampen vibrations emanating radially outwardly from the bone to the outer skin of the arm, but has no effect on vibrations of soft tissue, particularly vibrations emanating longitudinally or along the length of the arm.
U.S. Pat. No. 6,149,617 discloses a tennis elbow band that incorporates a removable thermal packet 20 therein. The thermal packet may be heated or chilled before it is inserted into the band. The band with thermal packet therein is tightened around a wearer's forearm to apply pressure and may be in combination with heating or cooling (if the thermal packet has been heated or chilled). The band has no effect on minimizing or dampening vibrations of soft tissue which travel in a longitudinal direction along a wearer's arm.
U.S. Pat. No. 5,338,290 shows a variable tension band formed as a laminate with multiple strips of elastic material 11 attached to one another with reinforcing ribs 13. The band is wrapped around a body part with sufficient tension to relieve pain. The ends of the band are joined together with hook and loop fasteners 12a, 12b. The patent indicates that joint pain may be relieved by wrapping the band around a body part at least one inch away from the joint. The band has no effect on vibrations which travel in a longitudinal direction along a wearer's arm or along a wearer's leg.
Bands have also been proposed for wrapping about the wrist to support the carpals and aid in preventing or treating carpal tunnel syndrome. See, e.g. U.S. Pat. Nos. 5,478,306 and 6,517,507. Such bands tightly encircle the wrist, but have no means for dampening vibrations of soft tissue which travel in a longitudinal direction from the hand across the wrist and along the wearer's arm.
U.S. Pat. No. 5,921,949 discloses a carpal tunnel wrist corrective support formed as a flexible strap with an inner surface onto which at least two compression pads are removably applied. The compression pads 41 and 42 are shown aligned with their major axis perpendicular to the longitudinal axis of the strap. The compression pads are fully adhered to the inner surface with hook and loop fasteners provided over the entire pad surface. There is no portion of a compression pad extending outwardly from the edges of the strap or left to freely vibrate without connection to the strap. Hence the strap has no means for dampening vibrations of soft tissue which travel in a longitudinal direction from the hand across the wrist and along the wearer's arm.
U.S. Pat. No. 6,585,674 shows a stretchable band having a wedge-shaped foam piece 14 adhered to one surface. The wedge-shaped foam piece supports a wearer's foot while the band is wrapped around the wearer's ankle. The band and wedge are intended to better align a wearer's foot and ankle to minimize injury to the knee. No means are provided for dampening vibrations of soft tissue which travel in a longitudinal direction from the foot across the ankle and along the wearer's leg.
Effective means for isolating and/or reducing impact-induced vibrations from traveling longitudinally along soft tissue of human extremities are still sought.